ARM: at91: at91sam9x5: add clocks for usb device

Add clocks for usb device, or else switch to CCF, the gadget
won't work.

Reported-by: Jiri Prchal <[e-mail]>
Signed-off-by: Bo Shen <[e-mail]>
Acked-by: Alexandre Belloni <[e-mail]>
Tested-by: Jiri Prchal <[e-mail]>
Signed-off-by: Nicolas Ferre <[e-mail]>
Signed-off-by: Olof Johansson <[e-mail]>

arch/arm/boot/dts/at91sam9x5.dtsi

···
 				reg = <0x00500000 0x80000
 				       0xf803c000 0x400>;
 				interrupts = <23 IRQ_TYPE_LEVEL_HIGH 0>;
+				clocks = <&usb>, <&udphs_clk>;
+				clock-names = "hclk", "pclk";
 				status = "disabled";
 
 				ep0 {